Dynamo-electric machine or motor.



PATENTED MAY 17, 1904.

LE. STOREY. DYNAMO ELECTRIC MACHINE OB. MOTOR.

APPLIUATION FILED SEPT. 15. 1903.

N0 MODEL.

WIIII/I/II/II/I/I/I/ll/II/ Huucul'o:

3W IWIILMWIA I UNITED STATES Patented May 1'7, 1904.

PATENT OFFICE.

IMLE E. STOREY, OF AMSTERDAM, NEW YORK.

DY-NAMO-ELECTRIC MACHINE OR MOTOR.

SPECIFICATION forming part of Letters Patent No. 760,086, dated May 17,1904.

Application file{. September 15, 1903. Serial No. 173,228- (No model.)

To all whom it may concern/.-

Be it known that I, IMLE STOREY, a citizen of the United States,residing at Amsterdam, in the county of Montgomery and State of NewYork, have invented certain new and useful Improvements inDynamo-Electric Machines or Motors, of which the following is a full,clear, and exact description.

This invention relates to dynamo-electric machines and motors, and hasspecial reference to the construction of the cores of the field-magnetwith a view to maintaining a uniform density of the lines of forcethroughout the air-gap to thereby prevent sparking at the commutator andincrease the range of regulation. The improved construction referred toconsists of a pole-piece having an internal chamber whose side wallsconverge at their inner ends and meet on a line very near the pole-faceand extend along the middle thereof. This construction permits the linesof force which traverse the length of the pole-pieces to spread out likea fan just before they cross the air-gap; but the stricture of themagnetic material at the middle point of the pole-faceformed by theconverging walls prevents this spreading beyond that point, but permitsthe spread to occur uniformly from each side toward the center, thusgiving an even distribution of the lines over the air-gap. In theoperation of the machine this even distribution will be somewhatdistorted by the rotation of the armature, since there will be the usualtendency of the lines to crowd toward that horn of the pole-piece fromwhich the armature is receding. This distortion, however, will occur ineach half of the air-gap, because the stricture of iron at the middle ofthe polar face prevents the lines in one half of the pole from crowdingover into the other half, and the result will be a substantiallyuniformity of density of the lines throughout the air-gap.

My invention also includes a detail of construction relating to themanner of holding the field-magnet coils in place.

In the accompanying drawings, Figure 1 is a section through a four-polefield-magnet, taken on a plane at right angles to the armature-shaft andshowing only two of the fieldmagnet coils in position. Fig. 2 is alongitudinal section of the same structure, taken on line a: r of Fig.1.; and Fig. 3 is a section on line 3 y of Fig. 1 through onlyone-halfof the structure. 1 I

A represents a cylinder or ring field-magnet frame having a width orlength in the direction of the armature shaft substantially equal to ora little greater than the armature. As shown, thisring has fourinwardly-projecting pole-piecesa. These pole-pieces are made-hollow, thechambers to therein being of substantially the same shape as-thepolepieces in the crosssection-that is, rectangular; but the two wallsof the chamber opposite each other in the direction of rotation convergetoward each other at equal angles, as shown at a (0 to a point very nearthe poleface, where only a thin web a of the metal is left.Substantially the same results will be obtained if the converging wallsof the chamber are on curved lines. I prefer, however, to make themstraight, so that the stricture at a will occur only at the middle pointof the pole-face and will quickly thicken out in each directiontherefrom.

1) indicates the field-magnet coils, which are ordinary rectangularcoils of wire slipped over the rectangular pole-pieces in the positionshown. To support them in place in such a manner that they can bereadily removed and replaced when necessary, I employ four plates 0,having two wings e angularly disposed and adapted to rest against oneside of the heads of two adjacent coils. The plate is placed against thecoils in the position shown and secured by means of a single bolt 0passing through its center and threaded into the fieldmagnet ring. Byremoving this bolt the plates, and consequently the field-coils, can betaken off and replaced.

In the operation of the machines the lines of force created in themagnet-cores a travel in parallel relation through the major part of thecore; but when they reach the points where the walls of the chamber inthe core converge they spread out in the form of a fan through thetriangular portion of iron, entirely filling each corner or horn of thepole-piece and flow-' ing with uniform density across the air-gap.

With the armature in motion there will be the usual tendency of thelines to crowd toward that corner or horn of the pole-piece from whichthe armature-surface recedes, and there will in practice be a somewhatgreater density of the lines in one half of the pole adjacent to thestricture a and in the other half adjacent to the point of the horn; butthe lines which crowd toward the stricture cannot spread into theopposite half on account of the magnetic resistance of the stricture.Hence the total number of lines of force traversing the field-magnet isdivided into two groups, and each group, though varying slightly indensity, does not present that wide variation of density which occurs inthe ordinary solid pole-pieces or those which have a substantiallyuniform thickness of metal along the polarj face.

I am aware that it has heretofore been proposed to regulate a motor byremoving a portion of the core and pole-face of the magnet; but it ispointed out thatthe removal of the pole-face robs a portion of theair-gap of its lines of force, whereas with my construction the lines offorce always traverse all parts of the air-gap, the integrity of thepole-face being maintained.

In order to prevent the lines of force which traverse the end portions aof the pole-pieces from spreading beyond the center line of the face ofthe pole, I carry the trough-shaped bottom of the chamber outward, asseen at a, to make the restriction equal to that at (0.

Having described my invention, 1 claim 1. In a dynamo-electric machineor motor, a field-magnet core and pole-piece having a chamber whoseopposite walls converge to a point near the pole-face and form astricture in the magnetic path at that point.

2. In a dynamo-electric machine or motor, a field-magnet having a coreand a continuous pole-face, said core having a rectangular chamber whosewalls opposite each other in the direction of armature rotation convergeat their inner ends until they meet on a line verynear the pole-face,for-the purpose set forth.

3. In a dynamo-electric machine or motor,

1 a field-magnet consisting of a ring having inwardly-projecting radialpole-pieces, coils of Wire on each pole-piece, retaining-plates arrangedbetween adjacent coils and resting against the heads thereof and a boltsecuring the plate to the ring, substantially as described. In witnesswhereof I subscribe my signature in presence of two witnesses.

lMLE E. STOREY. Witnesses:

FRANK S. OBER, VVALDO M. CHAPIN.

